The All Blacks have revealed that not all those players selected in their 30-man squad for the Tri-Nations are guaranteed a place at this year's Rugby World Cup.

A difference in injury replacement rules between the two tournaments could colour the final make-up of each squad with All Blacks assistant coach Steve Hansen suggesting their hand may be forced in terms of selection.

"There's no doubt that they're two different tournaments," said Hansen. "In the World Cup you can't replace a player and then bring them back through injury so that might have a bearing on how we select for the final World Cup squad. In the Tri-Nations if you get an injury you can replace that person and bring them back.

"We're going to try and win the Tri-Nations and Bledisloe Cup so to do that we want to pick the right squad to be able to do that," he said after a second two-day training camp for All Blacks hopefuls wrapped up in Wellington yesterday.

Hansen said they were keen to use the Tri-Nations to put some of the less experienced players under the microscope to assess whether they were up to playing in the World Cup. "There is an opportunity during the Tri-Nations to put some more polish on some people and just see what they can do and can't do," Hansen said.

One of the players who may get the chance to shine is first five-eighth Colin Slade who turns out for Canterbury tomorrow in a pre-season national provincial championship match against Wellington.

He will be watched by All Blacks coach Graham Henry and his assistant Wayne Smith to assess whether he has the form to act as Dan Carter's deputy. Slade is battling it out with Aaron Cruden to be the back-up pivot and Hansen said that they had all but nailed down their selections for the 30-man squad with just few slots to be decided.

Prop Tony Woodcock, utility back Isaia Toeava and fullback Israel Dagg were still weeks away from a return from injuries, while wing Hosea Gear was sidelined with a hamstring injury and loose forward Liam Messam limped out of training yesterday after rolling an ankle.

But Hansen said both Gear and Messam were in contention for the squad which is expected to come under intense scrutiny this year. "Every time a player puts on an All Blacks jersey he's on trial. There's an expectation of what he should do in that jersey and the biggest expectation comes from himself and the legacy of the jersey demands that. It'll be no different this year. Every time you play a test match you're on trial. Just because there's a World Cup at the end of it doesn't change that."

While the All Blacks coaches had one eye on the World Cup they were also determined to retain the Tri-Nations trophy and the Bledisloe Cup in the silverware cabinet at New Zealand Rugby Union's headquarters. "We'll try and pick the best team that we possible can, we always do. We don't have the luxury that some other countries have, that the World Cup is enough, we want to win everything.

"We'll attempt to go out and do that and if we don't it won't be because we were playing funny games, it'll be because we didn't do something right or we weren't good enough."

The All Blacks squad for the Tri-Nations and match against Fiji on July 22 will be named on Sunday.